Plug connection for two pairs of busbars

ABSTRACT

A plug connection for two pairs of busbars is described. A plug connection for two pairs of busbars is provided, with one free end of one pair of the busbars being formed as a plug and a free end of the other pair of the busbars being formed as a socket for receiving the plug and being fitted with a clamping device which allows an adjustable clamping force to be applied to the socket. An electrical connection between the two pairs of busbars is thereby provided in which the rails need not be screwed together, thus considerably simplifying assembly and greatly reducing assembly time as compared to known connection means.

FIELD OF THE INVENTION

The present invention relates to a plug connection for connecting twopairs of busbars.

BACKGROUND INFORMATION

In a converter device, the rail of the capacitor bank of theintermediate circuit and the rail of the inverter are screwed together.Because of this screw-coupling of the two pairs of busbars to oneanother, reductions occur in the cross-section area of the busbars inthe region of the screw locations, which means these regions are moreloaded electrically than the remaining sections of such busbars.Moreover, in the case of some converter devices, the capacitor bank isarranged spatially in front of the inverter, which means the screwlocations are poorly accessible. Possibly the rails have to belengthened in order to be able to make a screw connection, which canhave a negative effect on the inductance value of these busbars.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a connection for pairsof busbars which overcomes the problems of known busbar connectionmeans.

The present invention provides a plug connection for two pairs ofbusbars, with one free end of one pair of the busbars being formed as aplug and a free end of the other pair of the busbars being formed as asocket for receiving the plug and being fitted with a clamping devicewhich allows an adjustable clamping force to be applied to the socket.

By forming one free end of one pair of busbars as a socket for a plugcomponent of another pair of busbars, with the socket being providedwith a clamping device in such a way that an adjustable clamping forceacts on the socket, the two pairs of busbars can be fitted into eachother. With such a plug connection, the screw connections are dropped,which means the assembly can be considerably simplified and accomplishedin a much shorter time. The clamping device provides for the necessarycontacting of the busbars of these connecting pairs of busbars. Sincethe clamping device is adjustable, the plug connection according to thepresent invention can be adjusted in accordance with the contactingrequired for a particular application.

In one advantageous specific embodiment of the plug connection of thepresent invention, the clamping device juts out beyond the socket onboth sides. Because of this measure, the parts of the pairs of busbarswhich are fitted into each other do not need to be further altered,since the tension members of the clamping device are arranged outside ofthe socket. This provides an especially simple plug connection.

In another advantageous specific embodiment of the plug connection ofthe present invention, the busbars are bent up at the entry to thesocket. In this manner, the plug component of the second pair of busbarscan be guided more easily into the socket, since these bent-up busbarsserve as a catch-and-guide element for the socket.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view of two pairs of busbars that areconnected together in accordance with the present invention.

FIG. 2 shows a socket formed in a pair of busbars in accordance with thepresent invention.

FIG. 3 is a side view from the left of the connected busbars of FIG. 1.

DETAILED DESCRIPTION

FIG. 1 shows a perspective view from the right above two pairs ofbusbars 2 and 4 which are connected to one another in an electricallyconductive manner by means of the plug connection 6 according to thepresent invention. The pair of busbars 2 or 4 consists of 2 busbars 8and 10 or 12 and 14 which are separated from each other by an insulatinglayer 16 or 18. This insulating layer 16 or 18 juts out beyond the edgesof at least one busbar 8 or 10 and 12 or 14 respectively. The overhangof this insulating layer 16 or 18 is dependent upon the value of thevoltage applied to the busbars 8 and 10 or 12 and 14 and upon theenvironment. The overhang serves to enlarge the clearance leakage pathbetween the two busbars 8 and 10 or 12 and 14 so much that no voltageflashover develops.

As can be gathered from FIG. 1, these two low-inductive pairs of busbars2 and 4 are not screwed together, but rather are connected to oneanother in an electrically conductive manner by means of a plugconnection 6. In doing so, one free end 20 of the one pair of busbars 2is inserted into a socket 22 of the other pair of busbars 4. This socket22, which is pictured more precisely in detail in FIG. 2, is providedwith a clamping device 24.

The clamping device 24 consists of two clamping members 26 and 28, oneinsulating member 30 and at least two tension members 32. In addition,this clamping device 24 extends beyond the socket 22 of the pair ofbusbars 4 on both sides, in each case by a predetermined area, so thatthese areas can each contain a tension member 32. Due to theseconstructive measures, the clamping device 24 is attached to the socket22 in a manner assuring against loss of the attachment. By means of thetension members 32, one tension member being shown in greater detail inFIG. 3, a force is introduced on the outer surfaces of the socket 22 viathe clamping members 26 and 28, respectively, so that the socket 22 isprestressed. This clamping force is adjustable by means of the tensionmembers 32 and can be adjusted in accordance with the magnitude of thecurrent flowing in the busbars 8, 12 and 14, 10.

In this depicted specific embodiment of the plug connection 6, each ofits two parts are offset from the pair of busbars 2 or 4 belonging toit. This is one possible specific embodiment of the plug connection 6.How the plug connection 6 and the two pairs of busbars 2 and 4 arespatially situated relative to one another is determined by theapplication or by the spatial location of the objects which are supposedto be provided with rails by means of the two pairs of busbars 2 and 4connecting them together. In addition, the design of the plug connection6 in relationship to the pairs of busbars 2 and 4 is dependent upon theinsertion operation in the application.

FIG. 2 shows, in detail, the socket 22 of the plug connection 6according to the present invention. This socket 22 is a component of thepair of busbars 4. One free end of the pair of busbars 4 is shaped toform this socket 22. In the instance shown, the busbars 12 and are eachbent at their free ends by 90° in the same direction spatially, the freeend of the busbar 14 being bent so that it is displaced corresponding tothe thickness of the opening of the socket 22 to be formed. Theinsulating layer 18 which is arranged between the two busbars 12 and 14extends into the formed socket 22 at the base. At the entry to thesocket 22, the busbars 12 and 14 are each bent open so that a catchingarea is formed. In addition, the busbars 12 and 14 of this socket 22 areeach provided with a rectangular cutout 34 and 36 whose length dependson the plug depth of the connection. These cutouts 34 and 36 are used toreceive another tension member 32 of the clamping device 24. That is, athird and each further tension member 32 of the clamping device 24 needsin each case a cutout 34 and 36 in the socket 22. The width of thecutouts 34 and 36, which are arranged spatially parallel to one another,is determined by the form of the tension member 32.

FIG. 3 shows the form of a tension member 32 and the plug connection 6in detail. This representation is a side view from the left of therepresentation according to FIG. 1. Above the low-inductive pair ofbusbars 2 is an area bounded by means of a dot-dash line. In this area,for example, the capacitor bank of a pulse-controlled a.c. converter isarranged, which consists of a plurality of individual capacitors thatare electrically connected in parallel and in series. The rail of thecapacitor bank is formed by the busbars 8 and 10 and another busbar 38serves as the auxiliary busbar for the parallel connection and seriesconnection of the capacitors in the capacitor bank. The auxiliary busbar38 is likewise insulated from the busbar 10 by the insulating layer 16and is placed spatially parallel to the busbar 8. Below the pair ofbusbars 4 an area is likewise bounded by means of a dot-dash line. Inthis area, for example, an inverter of a pulse-controlled a.c. converteris arranged whose semiconductor components are secured on a heat sink.Another busbar 40 is arranged between the busbars 12 and 14 which ineach case is insulated from the busbars 12 and 14. These busbars 12, 14and 40 form the rail of the inverter, the busbars 12 and 14 formingconnections on the d.c. current side and the busbar 40 forming aconnection on the a.c. current side of the inverter. The rail 2 of thecapacitor bank must be connected in an electrically conductive manner tothe rail 4 of the inverter, this connection being accomplished by meansof the plug connection 6 according to the present invention.

As already mentioned, the plug connection 6 consists of a socket 22which is provided with a clamping device 24 and a part 20 that isinserted in the socket 22. The clamping device 24 consists of twoclamping members 26 and 28, one insulating member 30 and at least twotension members 32. A helical compression spring is provided, forexample, as a tension member 32. This helical compression spring 32consists of a screw 42 which is screwed through a bore hole in thesecond clamping member 28 and the insulating member 30 into a threadedhole in the first clamping member 26, and a compression spring 44 thatis arranged between the screw head and the second clamping member 28.The clamping members 26 and 28 are designed to be bar-shaped. If, forexample, these clamping members 26 and 28 are made of iron, then theinsulating member 30 ensures that the busbars 12 and 14 or 8 and 10 ofthe pairs of busbars 4 and 2 are not short-circuited. For this reason,the insulating member is designed, for example with an L-shape, whichmeans the clamping member 26 is sufficiently insulated from the livebusbars 8 and 14. However, the insulating member 30 can also be formedwith a U-shape, whereby the clamping member 26 is completely insulated.Between the insulating member 30 and the second clamping member 28, thetension member 32 is provided with two separator pieces 46 and 48 madeof insulating material. At the same time, the cross-section of theseparator piece 48 is smaller compared to the separator piece 46, butgreater in depth. The cross-sectional area of the separator pieces 46and 48 is, for example, square. The difference in size in thecross-section of these separator pieces 46 and 48 depends upon the valueof the voltage connected across the busbars 8 and 10. The difference insize in the depth of the separator piece 48 compared to the separatorpiece 46 is determined by the thicknesses of the busbar 10 and theinsulating layer 16 in comparison with the thickness of the busbar 8.Achieved by this shaping of the separator pieces 46 and 48 is that, ineach case, the necessary insulating clearances in the area of thetension members 32 between the busbars 8 and 10 or 12 and 14 of thepairs of busbars 2 or 4 are adhered to.

By means of the screws 42 and the compression springs 44 of the tensionmembers 32, the clamping force of the clamping device 24, which acts onthe outer sides of the socket 22, can be adjusted. Due to the clampingmembers 26 and 28, the force of the tension members 32 in each case isdistributed nearly uniformly over the entire outside of the socket 22.If the contacting of the busbars 10, 12 and 8, 14 should be improvedwithout at the same time substantially increasing the clamping force ofthe tension members 32, further tension members 32 can be providedwhich, for example, are arranged uniformly spaced along the clampingmembers 26 and 28. In the case of more than two tension members 32, thefree ends of the pairs of busbars 2 and 4, which are parts of the plugconnection 6, must be provided with corresponding rectangular cutouts34, 36.

In the handling of the plug connection 6 for two low-inductive pairs ofbusbars 2 and 4, first of all, a clamping force is adjusted by means ofthe tension members 32 according to the current that is to flow in thebusbars 8, 14, 12 and 10. After that, the pair of busbars 2 having thefree end 20, which is the plug component of the plug connection 6, isinserted into the socket 22. In doing so, this insertion operation canbe carried out frontally relative to the socket 22 or else by means of arotating motion. In the case of larger capacitor banks, the rotatingmotion is advisable in order to force the parts of the plug connection 6into engagement, since during this sequence of motion, the capacitorbank can support itself on another object, this point of support servingas the point of rotation.

In order to prevent the busbar 8 from becoming skewed with the separatorpiece 46, the corners of this separator piece 46 are chamfered. It isquite sufficient if, in each case, only the larger separator piece 46 ismachined in such a way since in the insertion operation, first of allthe busbar 8 comes in contact with the separator piece 46. Thus thisseparator piece 46 assumes guiding tasks as well.

What is claimed is:
 1. A plug connection for busbars comprising:a firstbusbar pair having an end formed as a plug; a second busbar pair havingan end formed as a socket for receiving the plug; and a clamping devicefor providing an adjustable clamping force on the socket, wherein theclamping device includes two clamping members, an insulating member andat least two tension members.
 2. The plug connection according to claim1, wherein the clamping device juts out beyond opposite sides of thesocket.
 3. The plug connection according to claim 1, wherein the busbarpairs are bent at the plug and socket ends.
 4. The plug connectionaccording to claim 1, wherein the plug connection includes at leastthree tension elements and the plug and socket ends of the busbar pairsinclude rectangular cutouts for accommodating the tension elements. 5.The plug connection according to claim 1, wherein the insulating memberhas an L-shaped cross-section.
 6. The plug connection according to claim1, wherein the clamping members are bar-shaped.
 7. The plug connectionaccording to claim 1, wherein each tension member includes a compressionspring and a screw.
 8. The plug connection according to claim 7,wherein:the screw of each tension member passes through a hole in thesecond clamping member and a hole in the insulating member and iscoupled with a threaded hole in the first clamping member, and thecompression spring of each tension member is mounted between a head ofthe screw and the second clamping member.
 9. The plug connectionaccording to claim 8, further comprising at least one separator piecebetween the second clamping member and the insulating member.
 10. Theplug connection according to claim 9, wherein the plug connectioncomprises at least two separator pieces of different sizes.
 11. The plugconnection according to claim 9, wherein the separator pieces have asquare shape and corners that are chamfered.